| Description: |
Comprises a series of drowned, steep-sided meander valleys on the L. Ontario Plain. The Sixteen Mile C arm (353785) is almost completely occupied by an open, shallow pond; the Fifteen Mile C arm (370790) has a small valley mouth pond which has a transition into alluvial plain marshes and scrubland features w/ a series of levees and moderately devel. meander patterns (oxbows, meander strands, m. ridge); Seventeen Mile C arm (352815), separated from the others by a cultivated plain, has a small valley mouth marsh and a rel. narrow, less well devel. floodplain pattern; the central arm (361805) contains a narrow valley w/out a meander pattern. The latter 2 valleys are restricted to the north of a railway line. Veg. patterns of these valleys include submergent & emergent aquatic meadows, marshes of Typha/Calamagrostis/Polygonum/Salix/Cornus, levee groves and thickets of Salix, as well as valley bottom seepage and swamp forests of Ulmus/Fraxinus/Salix. The pond slope forests are generally dry mesic, sandy loam Quercus/Acer/Pinus comlex w/ Acer/Fraxinus/Fagus pattern occuring on those narrower valleys. A well devel. esc. terrace valley complex, encompassing a large incised forested valley originates at the Rocking Falls of Fifteen Mile C., & extends into the Whirlpool Terrace and continues north into the drowned meander valley marshes. It consists of a narrow, steep-sided meander valley w/ several intermittent tributaries joining it half way across the terrace. It has 2 portions: a ne trending meander valley w/ a variety of floodplain basins and side valleys, and a more direct, north trending narrow downstream valley. Veg. complexes of this esc. terrace valley include slope, valley & basin forests of a variety of ages and sites undergoing various stages of succession including old fields and floodplain groves. A second esc terrace valley extends from a partially buried esc. face to L. Ontario along Sixteen Mile C. The valley forms a very well devel. broad meander pattern in the Whirlpool Terrace south of Hwy 8. Area almost entirely forested w/ a series of intermediate aged communities which include till slope and valley associations and an extensive broad valley of the Fiftenn Mile C. Esc exposure is restricted, occurring only locally at its southern edge and at a small waterfall (R85EAG01ONCA).
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